1. Field of the Invention
The present invention relates to an image forming apparatus and a density change suppressing method.
2. Description of the Related Art
In general, an image forming apparatus such as a printer, a copier, and a facsimile machine emits light onto a surface, which is to be scanned, and scans the surface using the light, thus forming latent image.
Such image forming apparatus includes a photosensitive drum having photosensitivity on the surface thereof serving as the surface which is to be scanned, and also includes a light source. Further, such image forming apparatus includes an optical scanning device for forming a latent image on the photosensitive drum surface by scanning the photosensitive drum surface in a main-scanning direction using light emitted from the light source, and also includes a developing unit including a developing roller that develops the latent image (see Japanese Patent Application Laid-open No. 2005-007697).
By the way, for example, when at least one of the photosensitive drum and the developing roller is eccentric, or when the cross section of at least one of the photosensitive drum and the developing roller is not a true circle, then, a gap between the photosensitive drum and the developing roller is changed when the photosensitive drum and developing roller are rotated. This change of the gap results in change of development, and also results in undesired density change in an image which is output from the image forming apparatus (also referred to as “output image”).
In recent years, demand for higher quality image is increasing, but it is difficult for the image forming apparatus disclosed in Japanese Patent Application Laid-open No. 2005-007697 to suppress the density change to the required level in the entire output image.
Therefore, it is desirable to provide an image forming apparatus capable of suppressing the density change to the required level in the entire output image.